In order to save costs, wiring and installation of electric power supply networks Power over Ethernet (PoE) systems have been developed, in which a power supply module supplies an operation module with a supply voltage via a data cable, i.e. the data and electric power are integrated on the same cable. Thus, in such a system the power supply module acts as a voltage source and supplies the operation module with electric power via the data cable and the operation module is supplied with a current by the power supply module via the data cable. The PoE systems are standardized under IEEE 802.3af. A power supply module that is arranged for being used in a PoE system is called Power over Ethernet Power Sourcing Equipment (PoE PSE) or in short Power Sourcing Equipment (PSE) and an operation module that is arranged for being used in a PoE system is called Power over Ethernet Powered Device (PoE PD) or in short Powered Device (PD).
The main advantage of PoE systems is that you can save the electric power supply cable and supply devices comprising an Ethernet interface with electric power or electricity via the data cable.
PDs can be IP telephones, cameras or wireless transmission devices consuming little power.
Furthermore, PoE is used in systems comprising lighting means, preferably LEDs, for supplying inter alia the lighting means with electric power. In such a PoE system a PD can correspond to an operating device for operating lighting means, preferably a LED string comprising at least one or more LEDs (arranged in series and/or in parallel), wherein the PD 104 is provided with a lighting means converter. PoE systems comprising lighting means can also comprise other electronic devices as PDs, such as sensors, actuators etc. For example with regard to electric devices installed in a building, a PoE system can comprise lighting means, shutter means for shading windows, air condition means etc. as PDs.
In systems comprising lighting means the provision of an emergency operation mode is a common function. In such a mode the lighting means can be operated to consume less power by for example reducing the light emission (dimming the lighting means) compared to the light emission in the normal operation mode. However, it is also possible that the lighting means are operated in an emergency operation mode in order to consume more power compared to the normal operation mode. During an emergency operation mode certain lighting means in the system can be switched off, while other lighting means can be kept on or can be switched on in the system.
The documents GB 1503684.1 and WO 2011/124723 A1 disclose systems comprising lighting means with an emergency operation mode.
In view of the prior art, it is an object of the present invention to implement an emergency operation mode in an PoE system comprising lighting means, so that operating modules/PDs that are arranged for operating the lighting means in an emergency operation mode can be triggered to operate the lighting means in the emergency operation mode during the operation phase of the PoE system.
This object is achieved by power supply modules, operation modules, Power over Ethernet (PoE) systems, a detection method and an emergency operation mode triggering method as described herein.